Treatment plug and method of anchoring a treatment plug and then removing a portion thereof

ABSTRACT

A treatment plug includes, a metal tubular expandable into sealing and anchoring engagement with a surrounding structure, the metal tubular having a shoulder at an inner radial surface thereof, and a composite plug sealable with the metal tubular and anchorable to the shoulder

BACKGROUND

Tubular systems, such as those used in the completion and carbon dioxidesequestration industries often employ anchors to positionally fix onetubular to another tubular. Although existing anchoring systems servethe function for which they are intended, the industry is alwaysreceptive to new systems and methods for anchoring tubulars.

BRIEF DESCRIPTION

Disclosed herein is a treatment plug. The treatment plug includes, ametal tubular expandable into sealing and anchoring engagement with asurrounding structure, the metal tubular having a shoulder at an innerradial surface thereof, and a composite plug sealable with the metaltubular and anchorable to the shoulder.

Further disclosed herein is a method of anchoring a treatment plug andthen removing a portion thereof. The method includes, positioning thetreatment plug having a metal tubular with a shoulder engaged with acomposite plug within a structure, swaging the metal tubular intosealing and anchoring engagement with the structure, plugging thecomposite plug, performing a treating operation, and drilling out thecomposite plug.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 depicts a cross sectional view of a treatment plug disclosedherein within a borehole in an earth formation; and

FIG. 2 depicts a cross sectional view of a portion of the treatment plugof FIG. 1.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosedapparatus and method are presented herein by way of exemplification andnot limitation with reference to the Figures.

Referring to FIG. 1, an embodiment of a treatment plug disclosed hereinis illustrated at 10. The treatment plug 10 includes, a metal tubular 14with a shoulder 18 at an inner radial surface 22 thereof, and acomposite plug 26 sealable with the metal tubular 14 and anchorable tothe shoulder 18. The metal tubular is sealingly and anchorablyattachable to a structure 30, shown herein as a borehole in an earthformation 34 in response to the metal tubular 14 being radiallyexpanded. The treatment plug 10 can include a seal 38, such as polymericsleeve, for example to aid in sealing the metal tubular 14 to thestructure 30. Additionally, one or more slips 42 can be positionedradially outwardly of the metal tubular 14 to facilitate anchoringengagement of the treatment plug 10 to the structure 30.

The composite plug 26 of the embodiment illustrated herein has acomposite lower ring 46 and composite bottom 66 that abut opposing sidesof the shoulder 18 to anchor the composite plug 26 to the metal tubular14. A seal 50, made of a polymer such as rubber, for example, iscompressible between the composite lower ring 46 and a composite upperring 54. Compression of the seal 50 causes radial expansion thereof andsubsequent sealing engagement to both the inner radial surface 22 of themetal tubular 14 and a surface 58 of a composite mandrel 62. The mandrel62 is attached to the composite bottom 66 and a sleeve 64 while thelower ring 46, the seal 50, and the upper ring 54 are able to moverelative to the mandrel 62. The attachment of the mandrel 62 to thesecomponents is sufficiently strong to prevent detachment while pulling onthe mandrel 62 relative to the metal tubular 14 during swaging of themetal tubular 14 and during pushing on the mandrel 62 relative to themetal tubular 14 during treating operations such as fracing of the earthformation 34, for example.

A setting tool 74 is operationally attachable to the composite plug 26,for example, through releasable engagement of a collet (not shown) on asleeve 78 of the setting tool 74 to the composite mandrel 62. Thisattachment allows a swage 82 of the setting tool 74 to move relative tothe sleeve 78 and the metal tubular 14 connected thereto. Movement ofthe swage 82 causes radial expansion of the metal tubular 14 therebyradially expanding the seal 38 into sealing engagement with thestructure 30 and radially expanding the slips 42 into anchoringengagement with the structure 30. Subsequent the radial expansion of themetal tubular 14 the setting tool 74 is retrievable, perhaps to surface,after detaching from the composite plug 26.

Referring additionally to FIG. 2, once the setting tool 74 has beenremoved, the treatment plug 10 is set to receive a plug 86, illustratedherein as a ball, seatable against a seat 90 on the composite mandrel62. The plug 86 can also be made of composite material to facilitatelater removal by drilling or milling with the rest of the componentsthat make up the composite plug 26. The composite plug 26 is attached tothe metal tubular 14 with sufficient strength, and the metal tubular 14is anchored to the structure 30 with sufficient strength to preventrelative movement between these parts during pressuring up against thecomposite plug 26 while plugged with the plug 86 during a treatingoperation such as a fracing operation or a pressure actuating event, forexample.

After any desired treatments are completed the composite plug 26 and theplug 86 are removable by machining them via a drilling or millingoperation. The treatment plug 10 is configured such that once thecomposite plug 26 portion has been removed a relatively large throughbore 94 of the metal tubular 14, is the only restriction that remainswithin the structure 30. The through bore 94 can be configured so that aradial dimension 98 thereof is greater than 80 percent of a greatestradial dimension 102 of the treatment plug 10 after it has been set.This large radial dimension 98 allows flow through the through bore 94for production of hydrocarbons, for example, with little restriction. Aplurality of the treatment plugs 10 can be employed within a single oneof the structures 30 and all of the treatment plugs 10 can subsequentlybe drilled out thereby leaving little restriction to flow therethrough.

While the invention has been described with reference to an exemplaryembodiment or embodiments, it will be understood by those skilled in theart that various changes may be made and equivalents may be substitutedfor elements thereof without departing from the scope of the invention.In addition, many modifications may be made to adapt a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to the particular embodiment disclosedas the best mode contemplated for carrying out this invention, but thatthe invention will include all embodiments falling within the scope ofthe claims. Also, in the drawings and the description, there have beendisclosed exemplary embodiments of the invention and, although specificterms may have been employed, they are unless otherwise stated used in ageneric and descriptive sense only and not for purposes of limitation,the scope of the invention therefore not being so limited. Moreover, theuse of the terms first, second, etc. do not denote any order orimportance, but rather the terms first, second, etc. are used todistinguish one element from another. Furthermore, the use of the termsa, an, etc. do not denote a limitation of quantity, but rather denotethe presence of at least one of the referenced item.

What is claimed is:
 1. A treatment plug comprising: a metal tubularexpandable into sealing and anchoring engagement with a surroundingstructure, the metal tubular having a shoulder at an inner radialsurface thereof; and a composite plug sealable with the metal tubularand anchorable to the shoulder.
 2. The treatment plug of claim 1,further comprising metal slips positioned radially outwardly of themetal tubular.
 3. The treatment plug of claim 1, further comprisingpolymeric seals positioned radially outwardly of the metal tubular. 4.The treatment plug of claim 1, wherein the metal tubular is radiallyexpandable in response to a swage run therethrough.
 5. The treatmentplug of claim 1, wherein after the treatment plug has been expanded andthe composite plug removed a smallest radial dimension of the treatmentplug remaining and defining a through bore is more than 80 percent of agreatest radial dimension of the treatment plug.
 6. The treatment plugof claim 5, wherein the smallest radial dimension of the treatment plugis defined by the metal tubular.
 7. The treatment plug of claim 1,wherein the composite plug includes no metal.
 8. The treatment plug ofclaim 1, wherein the composite plug is drillably removable from themetal tubular.
 9. The treatment plug of claim 1, wherein the compositeplug includes a seat that is sealingly receptive to a plug runthereagainst.
 10. The treatment plug of claim 9, wherein the treatmentplug supports fracing pressures built against a plug sealingly engagedagainst the seat.
 11. The treatment plug of claim 9, wherein the metaltubular and the shoulder are configured to support longitudinal loadsgenerated during swaging of the metal tubular into expanded sealing andanchoring engagement with the surrounding structure.
 12. The treatmentplug of claim 9, wherein the composite plug is configured to supportlongitudinal loads generated during swaging of the metal tubular intoexpanded sealing and anchoring engagement with the surroundingstructure.
 13. A method of anchoring a treatment plug and then removinga portion thereof, comprising: positioning the treatment plug having ametal tubular with a shoulder engaged with a composite plug within astructure; swaging the metal tubular into sealing and anchoringengagement with the structure; plugging the composite plug; performing atreating operation; and drilling out the composite plug.
 14. The methodof anchoring the treatment plug and then removing a portion thereof ofclaim 13, wherein the treating operation includes fracing a formation.15. The method of anchoring the treatment plug and then removing aportion thereof of claim 13, further comprising producing through themetal tubular after drilling out the composite plug.
 16. The method ofanchoring the treatment plug and then removing a portion thereof ofclaim 13, further comprising longitudinally compressing the metaltubular between the shoulder and a swaging head during the swaging. 17.The method of anchoring the treatment plug and then removing a portionthereof of claim 13, further comprising attaching a swaging tool to thecomposite plug.
 18. The method of anchoring the treatment plug and thenremoving a portion thereof of claim 13, further comprising leaving athrough bore having a minimum dimension that is more than 80 percent ofa greatest dimension of the treatment plug after drilling out thecomposite plug.